e1000: Don't set the Capabilities List bit

e1000: Don't set the Capabilities List bit

[Originally sent to qemu-kvm list, but I was redirected here]

The Capabilities Pointer is NULL, so this bit shouldn't be set. The state of
this bit doesn't appear to change any behavior on Linux/Windows versions we've
tested, but it does cause Windows' PCI/PCI Express Compliance Test to balk.

I happen to have a physical 82540EM controller, and it also sets the
Capabilities Bit, but it actually has items on the capabilities list to go
with it :)

Signed-off-by: dann frazier <dann.frazier@canonical.com>
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>